docs: def get_nic_hwaddr(nic):
      """Return the Media Access Control (MAC) for a network interface."""
      cmd = ['ip', '-o', '-0', 'addr', 'show', nic]
      ip_output = subprocess.check_output(cmd).decode('UTF-8')
      hwaddr = ""
      words = ip_output.split()
      if 'link/ether' in words:
          hwaddr = words[words.index('link/ether') + 1]
      return hwaddr